Mesoscale Precipitation Discussion 0025
NWS Weather Prediction Center College Park MD
1017 PM EST Thu Feb 06 2025

Areas affected...much of California

Concerning...Heavy rainfall...Flash flooding possible

Valid 070316Z - 070916Z

Summary...Flood/flash flood potential should continue on at least
an isolated basis through 09Z/1a PST.  An additional 1-2 inches of
rainfall is expected along windward locations of the Sierra, and
locally higher amounts cannot be ruled out.

Discussion...Flood/flash flood potential is expected to continue
through at least 09Z this evening.  Persistent lift associated
with an upstream mid-level wave west of Oregon continues to
support scattered to widespread shower activity across the region.
 Additionally, strong southerly low-level flow (40-50 knots at
850mb) continues to support local terrain enhancement to rain
rates across windward locations of the Sierra, where hourly rain
rates nearing 0.25 inch were noted per MRMS near/southeast of
Redding.  These rates have contributed to isolated flash flooding
and mudslides.   This regime is expected to persist for several
more hours, with additional rainfall accumulations of 1-2 inches
expected.  Wet (and moistening) ground conditions and ongoing
rainfall is expected to continue to foster at least isolated
instances of excessive runoff/flood impacts.

Around/after 09Z, models suggest the low-level flow enhancing
rainfall rates this evening will begin to weaken slightly. 
Moderate to heavy rainfall should still remain in the area,
although a gradual decrease in the overall coverage of the
heaviest rainfall should commence.  A gradual lessening of the
flash flood risk is also expected during this timeframe.

Cook

ATTN...WFO...EKA...HNX...MFR...MTR...REV...STO...

ATTN...RFC...CNRFC...NWC...

LAT...LON   41242187 40582099 39452012 38001937 37381921
            37161927 37201984 38132077 38812152 38512191
            37612172 36792147 36512163 37682257 40012355
            40912315 41172265